Lubricating compositions



United States Patent LUBRICATING COB [POSITIONS Paul H. Williams, Berkeley, Lawrence B. Scott, Lafayette, and Victor N. Borsolf, Berkeley, Calif., assignors to Shell Development Company, Emeryville, Califi, a corporation of Delaware No Drawing. Application July 18,1952, Serial No. 299,741

12 Claims. (Cl. 252-18) This invention relates to lubricants particularly suitable for lubrication under extreme operating conditions, such as under extreme pressure, high speed and high temperature conditions.

It is well known that the high pressure occurring in certain types of gears and bearings may cause a film of lubricant to rupture with consequent damage to the machinery. It has been shown that base lubricants such as mineral oil and/or synthetic oil can be improved with regard to their protective efiect particularly on rubbing surfaces by the addition of certain substances, so that excessive wear, scufiing and seizure, which normally follow a break in the film of lubricant, can be prevented even under very unfavorable pressure and speed conditions. Lubricants possessing this highly desirable property are called extreme pressure lubricants.

It is known that certain elements or compounds of elements of the type of chlorine, sulfur, phosphorus and lead are capable of imparting extreme pressure properties to lubricants, which may be lubricating oils and greases, when blended therewith. Among the compounds heretofore used are notable the lead soaps, phosphoric acid esters, free sulfur, and certain chlorinated organic compounds. A principal objection to extreme pressure compounds of this class is that they are highly reactive with contacting surfaces causing etching, corrosion and discoloration of said surfaces. Another objection to reactive extreme pressure agents is that they alter the original chemical nature of the contacting surface'and this, under certain conditions, is undesirable. tionally, because of the activity of agents of the type under discussion they usually deplete rapidly resulting in, at the very best, only a temporary solution to extreme pressure lubrication.

It has now been discovered that improved extreme pressure lubricants can be obtained by incorporating into a base lubricant, minor amounts of certain inorganic salts in the form of colloidal particles, of from less than 1 to 10 microns and preferably from less than 0.5 to 3 microns, said colloidal salts being capable of forming under conditions of use viscous liquids or glass-like solids which have a greater aflinity for contacting surfaces to be lubricated than the base lubricant or liquid carrier.

The colloidal inorganic salts include metal and/ or ammonium acid phosphates, silicates, antimonates, molybdates and mixtures thereof. Specific examples of compounds which are particularly suited in compositions of this invention include: sodium, potassium and ammonium mono and dihydrogen phosphates, acid silicates and mixtures thereof;

Salts and their mixtures of this invention which might lack desired oil solubility can be sufiiciently oil solubilized in desirable base carriers by mechanical means such as described in U. S. Patent 2,529,461 or by grinding in colloidal or paint mills or any other suitable means. Still another method 01 maintaining the salts of this invention in bases such as oils is by means of dispersingagents.

Addiice In selecting suitable dispersing agents, they must be of such a nature as to be oil soluble, have good dispersing properties, but possess less of an affinity or attractiveness for the surface to be lubricated than the salts of this invention. Dispersing agents which are practically preferred include esters of polyhydric alcohols and derivatives thereof, such as propylene glycol monolaurate, propyl glycol mono-cleats, propylene glycol monostearate, oleic acid derivative of polyoxyethylene sorbitol (6-1096, Atlas Powder Co.), polyoxyalkylene glucose tetrastearate (G-1164, Atlas Powder Co.), glycerol sorbitan laurate (6-672, Atlas Powder Co.), and the like.

Salts of this invention are excellent activating 'or spiking agents for well known extreme pressure agents such as organic phosphates, phosphonates, sulfur containing compounds, chlorine containing compounds and mixtures thereof. By spiking agents is meant materials capable of activating and improving the load carrying and extreme pressure properties of the general class of compound enumerated above, and particularly such compounds as'the full and partial esters of trichloromethanephosphonic acid and their salts (monobutyl trichloromethanephosphonate, di-2-ethylhexylamine salt of monobutyl trichloromethanephosphonate), sulfurized and/or phosphorized fatty oils and waxes, chlorinated waxes and the like.

Base oils to which agents of this invention are added may be selected from a variety of natural oils such as parafiinic, naphthenic, and mixed base mineral oils having a viscosity range such as from 40 at 100 F., SUS, to up to 1000 SUS at 210 F. In addition, synthetic oils may be used such as polymerized olefins, alkylated aromatics; polyalkyl silicone polymers, e. g., liquid dimethyl silicone polymer, other silicone polymers; HzS-adducts of unsaturated ethers and thioethers, e. g., H28 adduct of diallyl ether; esters, e. g., di(2-ethylhexyl) sebacate. Mixtures of natural and synthetic oils can be used. Under certain conditions of lubrication, minor amounts of a fixed oil such as castor oil, lard oil and the like, may be admixed with a hydrocarbon oil and/ or synthetic oil.

The general formulation of compositions of this invention can be represented by:

Amolnt (ltiercent w Extreme Pressure Agent(s) y Broad Preferred Range Range Certain inorganic salts, e. g., KHIPO, (N114) BzPQl, etc 0. 01-10 0. 1-5 Dispel-slug (optional): Preferred ester type.... 1-20 1-10 Optional Additive: Organic extreme pressure agents, detergents, anti-oxidants, corrosion inhibitors, etc 0. 01-5 0. 1-2

Preferred compositions of this invention are illustrated by the following examples:

Composition A Co.) percent.. 6 Mineral oil Balance 3 Composition E NaHzPOi. "percent" 2 Glycerol sorbitan laurate do 6 Mineral oil Balance Composition F HzPO4+HaBO3 (50-50 mixture) percent 2 Glycerol sorbitan laurate do 6 Mineral oil Balance Composition G KHZPCM pe1'cent 2 Di-Z-ethylhexyl amine salt of monobutyl trichloromethane phosphonate percent 1 Mineral oil Balance Composition H (NHQI-IzPOr percent 2 Di-Z-ethylhexyl amine salt of monobutyl trichloromethane phosphonate percent 1 Mineral oil Balance Composition J KJ'I2PO4 percent- 2 Ucon Fluid (polyether compound sold by Carbide and Carbon Chemical Co.) Balance Composition K KH2PO4 percent 2 Glycerol sorbitan laurate (G-672, Atlas Powder Co.) percent 6 Di-Z-ethylhexyl sebacate Balance Composition L (NHQHzPOi percent 2 Glycerol sorbitan laurate do 6 Mineral oil Balance Compositions of this invention were evaluated for their extreme pressure properties on a Spur Gear Machine, which consists essentially of two geometrically similar pairs of gears connected by two parallel shafts. The gear pairs are placed in separate gear boxes, which also contain the supporting ball bearings. One of the shafts consists of two sections connected by a'coupling. Loading is accomplished by locking one side of the coupling and applying torque to the other. The conditions of the test were:

TEST RESULTS {3,000 R. P. M. pinion speed, ambient temp, 10 can/soc. flow rate} Addendum Tooth Composition Score Tooth Face Load,

Load. lb. Contact lb./inch Bear Load Face Mineral oil 6 Full 432 Composition A 60 One-hali 8, 640 Composition D. 30 Full 5, 760 Composition L. l 70 One-ham 10, 080 Composition E St) Full 5. 160

Compositions of this invention were further tested in the Hypoid Gear Machine and under modified Ll9-645 engine test conditions as described in the 1946 CRC Handbook published by the Coordination Research Council.

TEST RESULTS tri-tertiary-butyl phenol and the like; amino phenols as benzyl amino phenols; amines such as dibutyl-phenylene diamine, diphenyl amine, N-phenyl-beta-naphthylamine,

N-phenyl-alpha-naphthylamine, dinaphthyl amine.

Corrosion inhibitors or anti-rusting compounds may also be present, such as dicarboxylic acids of 16 and more carbon atoms; organic compounds containing acidic radical in close proximity to a nitrile, nitro or nitroso group (e. g., alpha-cyanostearic acid).

Wear reducing agents which may be used comprise: esters of phosphorus acids such as triaryl, alkyl hydroxy aryl, or arallsyl phosphates, thicphosphatcs or phosphites and the like; neutral aromatic sulfur compounds of relatively high boiling temperatures such as diaryl sulfides, diaryl disulfides, alkyl aryl disulfides, e. g., diphenyl sulfide, diphenol sulfide, dicresol sulfide, dixylenol sulfide, methyl butyl diphenol sulfide, dibenzyl sulfide, corresponding diand tri-sulfides, and the like; sulfurized fatty oils or esters of fatty acids and monohydric alcohols, e. g., sperm oil, jojoba oil, etc; in which the sulfur is strongly bonded; sulfurized long chain olcfins such as may be obtained by dehydrogenation or cracking of wax; sulfurized phosphorized fatty oils or acids, phosphorus acid esters having sulfurized organic radicals, such as esters of phosphoric or phosphorus acids with sulfurized hydroxy fatty acids; chlorinated hydrocarbons, such as chlorinated paraffin aromatic hydrocarbons, terpenes, mineral lubricating oil, etc; or chlorinated esters of fatty acids containing the chlorine in position other than alpha position.

Additional ingredients may comprise oil-soluble urea or thiourea derivatives, e. g., urethanes, allophanates, carbazides, carbazones, etc; polyisobutylene polymers, unsaturated polymerized esters of fatty acids and monohydric alcohols and other high molecular weight oilsoluble compounds.

Depending upon the additive used and conditions under which it is used, the amount of additive used may vary from 0.01 to 2% or higher.

It is to be understood that while the features of the invention have been described and illustrated in connection with certain specific examples, the invention, however, is not to be limited thereto or otherwise restricted, except by the prior art and the broad scope of the disclosed invention.

* We claim as our invention:

1. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from 0.1 to 10% of a salt selected from the group consisting of sodium dihydrogen.

phosphate, potassium dihydrogen phosphate and ammonium dihydrogen phosphate, said salt being in colloidal dimensions of from about 1 to 10 microns.

2. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from 0.1 to 10% of a salt selected from the group consisting of sodium dihydrogen phosphate, potassium dihydrogen phosphate and ammonium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns, and a minor amount sufficient to solubilize said inorganic salt of an ester of a polyhydric alcohol and a long-chain aliphatic carboxylic acid.

3. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from 0.1 to 10% of a salt selected from the group consisting of sodium di-.

hydrogen phosphate, potassium dihydrogen phosphate and ammonium dihydrogen phosphate in colloidal dimensions of from about 1 to microns, and a minor amount suflicient to solubilize said inorganic salt of glycerol sorbitan laurate.

4. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of potassium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns.

5. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of ammonium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns.

6. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of sodium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns.

7. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of potassium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns, and a minor amount sufiicient to solubilize said potassium dihydrogen phosphate of glycerol sorbitan laurate.

8. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of ammonium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns, and a minor amount sufficient to solubilize said ammonium dihydrogen phosphate of glycerol sorbitan laurate.

9. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of sodium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns, and a minor amount suflicient to solubilize said sodium dihydrogen phosphate of glycerol sorbitan laurate.

10. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of potassium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns, and from about 0.01 to about 2% of di-Z-ethylhexyl amine salt of monobutyl trichloromethanephosphonic acid ester.

11. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of ammonium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns, and from about 0.01 to about 2% of di-2-ethylhexy1 amine salt of monobutyl trichloromethanephosphonic acid ester.

12. A lubricating composition adapted for extreme pressure use comprising a major amount of mineral lubricating oil having incorporated therein from .01 to 10% of sodium dihydrogen phosphate in colloidal dimensions of from about 1 to 10 microns, and from about 0.01 to about 2% of di-2-ethy1hexyl amine salt of monobutyl trichloromethanephosphonic acid ester.

References Cited in the file of this patent UNITED STATES PATENTS 2,079,051 Sullivan et al. May 4, 1937 2,455,659 Duncan et al. Dec. 7, 1948 2,530,837 Orozco et al. Nov. 21, 1950 OTHER REFERENCES Atlas Surface Active Agents, publication of Atlas Powder Co., Wilmington, Delaware, 1950, pages 2 and 10. (Copy in Div. 64.) 

1. A LUBRICATING COMPOSITION ADAPTED FOR EXTREME PRESSURE USE COMPRISING A MAJOR AMOUNT OF MINERAAL LUBRICATING OIL HAVING INCORPORATED THEREIN FROM 0.1 TO 10% OF A SALT SELECTED FROM THE GROUP CONSISTING OF SODIUM DIHYDROGEN PHOSPHATE, POTASSIUM DIHYDROGEN PHOSPHATE AND AMMONIUM DIHYDROGEN PHOSPHATE, SAID SALT BEING IN COLLOIDAL DIMENSIONS OF ABOUT 1 TO 10 MICRONS. 